Intracranial meningioma: A review of recent and emerging data on the utility of preoperative imaging for management.

Meningiomas are the most common neoplasms of the central nervous system, accounting for approximately 40% of all brain tumors. Surgical resection represents the mainstay of management for symptomatic lesions. Preoperative planning is largely informed by neuroimaging, which allows for evaluation of anatomy, degree of parenchymal invasion, and extent of peritumoral edema. Recent advances in imaging technology have expanded the purview of neuroradiologists, who play an increasingly important role in meningioma diagnosis and management. Tumor vascularity can now be determined using arterial spin labeling and dynamic susceptibility contrast-enhanced sequences, allowing the neurosurgeon or neurointerventionalist to assess patient candidacy for preoperative embolization. Meningioma consistency can be inferred based on signal intensity; emerging machine learning technologies may soon allow radiologists to predict consistency long before the patient enters the operating room. Perfusion imaging coupled with magnetic resonance spectroscopy can be used to distinguish meningiomas from malignant meningioma mimics. In this comprehensive review, we describe key features of meningiomas that can be established through neuroimaging, including size, location, vascularity, consistency, and, in some cases, histologic grade. We also summarize the role of advanced imaging techniques, including magnetic resonance perfusion and spectroscopy, for the preoperative evaluation of meningiomas. In addition, we describe the potential impact of emerging technologies, such as artificial intelligence and machine learning, on meningioma diagnosis and management. A strong foundation of knowledge in the latest meningioma imaging techniques will allow the neuroradiologist to help optimize preoperative planning and improve patient outcomes.

Influence of hospital volume on nephrectomy mortality and complications: a systematic review and meta-analysis stratified by surgical type.

OBJECTIVES: The provision of complex surgery is increasingly centralised to high-volume (HV) specialist hospitals. Evidence to support nephrectomy centralisation however has been inconsistent. We conducted a systematic review and meta-analysis to determine the association between hospital case volumes and perioperative outcomes in radical nephrectomy, partial nephrectomy and nephrectomy with venous thrombectomy. METHODS: Medline, Embase and the Cochrane Library were searched for relevant studies published between 1990 and 2016. Pooled effect estimates for nephrectomy mortality and complications were calculated for each nephrectomy type using the DerSimonian and Laird random-effects model. Sensitivity analyses were performed to examine the effects of heterogeneity on the pooled effect estimates by excluding studies with the heaviest weighting, lowest methodological score and most likely to introduce bias from misclassification of standardised hospital volume. RESULTS: Some 226 372 patients from 16 publications were included in our review and meta-analysis. Considerable between-study heterogeneity was noted and only a few reported volume-outcome relationships specifically in partial nephrectomy or nephrectomy with venous thrombectomy.HV hospitals were correlated with a 26% and 52% reduction in mortality for radical nephrectomy (OR 0.74, 95% CI 0.61 to 0.90, p<0.01) and nephrectomy with venous thrombectomy (OR 0.48, 95% CI 0.29 to 0.81, p<0.01), respectively. In addition, radical nephrectomy in HV hospitals was associated with an 18% reduction in complications (OR 0.82, 95% CI 0.73 to 0.92, p<0.01). No significant volume-outcome relationship in mortality (OR 0.84, 95% CI 0.31 to 2.26, p=0.73) or complications (OR 0.85, 95% CI 0.55 to 1.30, p=0.44) was observed for partial nephrectomy. CONCLUSIONS: Our findings suggest that patients undergoing radical nephrectomy have improved outcomes when treated by HV hospitals. Evidence of this in partial nephrectomy and nephrectomy with venous thrombectomy is however not yet clear and could be secondary to the low number of studies included and the small patient number in our analyses. Further investigation is warranted to establish the full potential of nephrectomy centralisation particularly as existing evidence is of low quality with significant heterogeneity.

Postactivation potentiation in professional rugby players: optimal recovery.

Following a bout of high-intensity exercise of short duration (preload stimulus), the muscle is in both a fatigued and a potentiated (referred to as postactivation potentiation) state. Consequently, subsequent muscle performance depends on the balance between these 2 factors. To date, there is no uniform agreement about the optimal recovery required between the preload stimulus and subsequent muscle performance to gain optimal performance benefits. The aim of the present study was to determine the optimal recovery time required to observe enhanced muscle performance following the preload stimulus. Twenty-three professional rugby players (13 senior international players) performed 7 countermovement jumps (CMJs) and 7 ballistic bench throws at the following time points after a preload stimulus (3 repetition maximum [3RM]): baseline, approximately 15 seconds, and 4, 8, 12, 16, and 20 minutes. Their peak power output (PPO) was determined at each time point. Statistical analyses revealed a significant decrease in PPO for both the upper (856 +/- 121 W vs. 816 +/- 121 W, p < 0.001) and the lower (4,568 +/- 509 W vs. 4,430 +/- 495 W, p = 0.005) body when the explosive activity was performed approximately 15 seconds after the preload stimulus. However, when 12 minutes was allowed between the preload stimulus and the CMJ and ballistic bench throws, PPO was increased by 8.0 +/- 8.0% and 5.3 +/- 4.5%, respectively. Based on the above results, we conclude that muscle performance (e.g., power) can be significantly enhanced following a bout of heavy exercise (preload stimulus) in both the upper and the lower body, provided that adequate recovery (8-12 minutes) is given between the preload stimulus and the explosive activity.